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Patrick Williamsc124f4f2015-09-15 14:41:29 -05001# interp.py - shell interpreter for pysh.
2#
3# Copyright 2007 Patrick Mezard
4#
5# This software may be used and distributed according to the terms
6# of the GNU General Public License, incorporated herein by reference.
7
8"""Implement the shell interpreter.
9
10Most references are made to "The Open Group Base Specifications Issue 6".
11<http://www.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html>
12"""
13# TODO: document the fact input streams must implement fileno() so Popen will work correctly.
14# it requires non-stdin stream to be implemented as files. Still to be tested...
15# DOC: pathsep is used in PATH instead of ':'. Clearly, there are path syntax issues here.
16# TODO: stop command execution upon error.
17# TODO: sort out the filename/io_number mess. It should be possible to use filenames only.
18# TODO: review subshell implementation
19# TODO: test environment cloning for non-special builtins
20# TODO: set -x should not rebuild commands from tokens, assignments/redirections are lost
21# TODO: unit test for variable assignment
22# TODO: test error management wrt error type/utility type
23# TODO: test for binary output everywhere
24# BUG: debug-parsing does not pass log file to PLY. Maybe a PLY upgrade is necessary.
25import base64
26import cPickle as pickle
27import errno
28import glob
29import os
30import re
31import subprocess
32import sys
33import tempfile
34
35try:
36 s = set()
37 del s
38except NameError:
39 from Set import Set as set
40
41import builtin
42from sherrors import *
43import pyshlex
44import pyshyacc
45
46def mappend(func, *args, **kargs):
47 """Like map but assume func returns a list. Returned lists are merged into
48 a single one.
49 """
50 return reduce(lambda a,b: a+b, map(func, *args, **kargs), [])
51
52class FileWrapper:
53 """File object wrapper to ease debugging.
54
55 Allow mode checking and implement file duplication through a simple
56 reference counting scheme. Not sure the latter is really useful since
57 only real file descriptors can be used.
58 """
59 def __init__(self, mode, file, close=True):
60 if mode not in ('r', 'w', 'a'):
61 raise IOError('invalid mode: %s' % mode)
62 self._mode = mode
63 self._close = close
64 if isinstance(file, FileWrapper):
65 if file._refcount[0] <= 0:
66 raise IOError(0, 'Error')
67 self._refcount = file._refcount
68 self._refcount[0] += 1
69 self._file = file._file
70 else:
71 self._refcount = [1]
72 self._file = file
73
74 def dup(self):
75 return FileWrapper(self._mode, self, self._close)
76
77 def fileno(self):
78 """fileno() should be only necessary for input streams."""
79 return self._file.fileno()
80
81 def read(self, size=-1):
82 if self._mode!='r':
83 raise IOError(0, 'Error')
84 return self._file.read(size)
85
86 def readlines(self, *args, **kwargs):
87 return self._file.readlines(*args, **kwargs)
88
89 def write(self, s):
90 if self._mode not in ('w', 'a'):
91 raise IOError(0, 'Error')
92 return self._file.write(s)
93
94 def flush(self):
95 self._file.flush()
96
97 def close(self):
98 if not self._refcount:
99 return
100 assert self._refcount[0] > 0
101
102 self._refcount[0] -= 1
103 if self._refcount[0] == 0:
104 self._mode = 'c'
105 if self._close:
106 self._file.close()
107 self._refcount = None
108
109 def mode(self):
110 return self._mode
111
112 def __getattr__(self, name):
113 if name == 'name':
114 self.name = getattr(self._file, name)
115 return self.name
116 else:
117 raise AttributeError(name)
118
119 def __del__(self):
120 self.close()
121
122
123def win32_open_devnull(mode):
124 return open('NUL', mode)
125
126
127class Redirections:
128 """Stores open files and their mapping to pseudo-sh file descriptor.
129 """
130 # BUG: redirections are not handled correctly: 1>&3 2>&3 3>&4 does
131 # not make 1 to redirect to 4
132 def __init__(self, stdin=None, stdout=None, stderr=None):
133 self._descriptors = {}
134 if stdin is not None:
135 self._add_descriptor(0, stdin)
136 if stdout is not None:
137 self._add_descriptor(1, stdout)
138 if stderr is not None:
139 self._add_descriptor(2, stderr)
140
141 def add_here_document(self, interp, name, content, io_number=None):
142 if io_number is None:
143 io_number = 0
144
145 if name==pyshlex.unquote_wordtree(name):
146 content = interp.expand_here_document(('TOKEN', content))
147
148 # Write document content in a temporary file
149 tmp = tempfile.TemporaryFile()
150 try:
151 tmp.write(content)
152 tmp.flush()
153 tmp.seek(0)
154 self._add_descriptor(io_number, FileWrapper('r', tmp))
155 except:
156 tmp.close()
157 raise
158
159 def add(self, interp, op, filename, io_number=None):
160 if op not in ('<', '>', '>|', '>>', '>&'):
161 # TODO: add descriptor duplication and here_documents
162 raise RedirectionError('Unsupported redirection operator "%s"' % op)
163
164 if io_number is not None:
165 io_number = int(io_number)
166
167 if (op == '>&' and filename.isdigit()) or filename=='-':
168 # No expansion for file descriptors, quote them if you want a filename
169 fullname = filename
170 else:
171 if filename.startswith('/'):
172 # TODO: win32 kludge
173 if filename=='/dev/null':
174 fullname = 'NUL'
175 else:
176 # TODO: handle absolute pathnames, they are unlikely to exist on the
177 # current platform (win32 for instance).
178 raise NotImplementedError()
179 else:
180 fullname = interp.expand_redirection(('TOKEN', filename))
181 if not fullname:
182 raise RedirectionError('%s: ambiguous redirect' % filename)
183 # Build absolute path based on PWD
184 fullname = os.path.join(interp.get_env()['PWD'], fullname)
185
186 if op=='<':
187 return self._add_input_redirection(interp, fullname, io_number)
188 elif op in ('>', '>|'):
189 clobber = ('>|'==op)
190 return self._add_output_redirection(interp, fullname, io_number, clobber)
191 elif op=='>>':
192 return self._add_output_appending(interp, fullname, io_number)
193 elif op=='>&':
194 return self._dup_output_descriptor(fullname, io_number)
195
196 def close(self):
197 if self._descriptors is not None:
198 for desc in self._descriptors.itervalues():
199 desc.flush()
200 desc.close()
201 self._descriptors = None
202
203 def stdin(self):
204 return self._descriptors[0]
205
206 def stdout(self):
207 return self._descriptors[1]
208
209 def stderr(self):
210 return self._descriptors[2]
211
212 def clone(self):
213 clone = Redirections()
214 for desc, fileobj in self._descriptors.iteritems():
215 clone._descriptors[desc] = fileobj.dup()
216 return clone
217
218 def _add_output_redirection(self, interp, filename, io_number, clobber):
219 if io_number is None:
220 # io_number default to standard output
221 io_number = 1
222
223 if not clobber and interp.get_env().has_opt('-C') and os.path.isfile(filename):
224 # File already exist in no-clobber mode, bail out
225 raise RedirectionError('File "%s" already exists' % filename)
226
227 # Open and register
228 self._add_file_descriptor(io_number, filename, 'w')
229
230 def _add_output_appending(self, interp, filename, io_number):
231 if io_number is None:
232 io_number = 1
233 self._add_file_descriptor(io_number, filename, 'a')
234
235 def _add_input_redirection(self, interp, filename, io_number):
236 if io_number is None:
237 io_number = 0
238 self._add_file_descriptor(io_number, filename, 'r')
239
240 def _add_file_descriptor(self, io_number, filename, mode):
241 try:
242 if filename.startswith('/'):
243 if filename=='/dev/null':
244 f = win32_open_devnull(mode+'b')
245 else:
246 # TODO: handle absolute pathnames, they are unlikely to exist on the
247 # current platform (win32 for instance).
248 raise NotImplementedError('cannot open absolute path %s' % repr(filename))
249 else:
250 f = file(filename, mode+'b')
251 except IOError as e:
252 raise RedirectionError(str(e))
253
254 wrapper = None
255 try:
256 wrapper = FileWrapper(mode, f)
257 f = None
258 self._add_descriptor(io_number, wrapper)
259 except:
260 if f: f.close()
261 if wrapper: wrapper.close()
262 raise
263
264 def _dup_output_descriptor(self, source_fd, dest_fd):
265 if source_fd is None:
266 source_fd = 1
267 self._dup_file_descriptor(source_fd, dest_fd, 'w')
268
269 def _dup_file_descriptor(self, source_fd, dest_fd, mode):
270 source_fd = int(source_fd)
271 if source_fd not in self._descriptors:
272 raise RedirectionError('"%s" is not a valid file descriptor' % str(source_fd))
273 source = self._descriptors[source_fd]
274
275 if source.mode()!=mode:
276 raise RedirectionError('Descriptor %s cannot be duplicated in mode "%s"' % (str(source), mode))
277
278 if dest_fd=='-':
279 # Close the source descriptor
280 del self._descriptors[source_fd]
281 source.close()
282 else:
283 dest_fd = int(dest_fd)
284 if dest_fd not in self._descriptors:
285 raise RedirectionError('Cannot replace file descriptor %s' % str(dest_fd))
286
287 dest = self._descriptors[dest_fd]
288 if dest.mode()!=mode:
289 raise RedirectionError('Descriptor %s cannot be cannot be redirected in mode "%s"' % (str(dest), mode))
290
291 self._descriptors[dest_fd] = source.dup()
292 dest.close()
293
294 def _add_descriptor(self, io_number, file):
295 io_number = int(io_number)
296
297 if io_number in self._descriptors:
298 # Close the current descriptor
299 d = self._descriptors[io_number]
300 del self._descriptors[io_number]
301 d.close()
302
303 self._descriptors[io_number] = file
304
305 def __str__(self):
306 names = [('%d=%r' % (k, getattr(v, 'name', None))) for k,v
307 in self._descriptors.iteritems()]
308 names = ','.join(names)
309 return 'Redirections(%s)' % names
310
311 def __del__(self):
312 self.close()
313
314def cygwin_to_windows_path(path):
315 """Turn /cygdrive/c/foo into c:/foo, or return path if it
316 is not a cygwin path.
317 """
318 if not path.startswith('/cygdrive/'):
319 return path
320 path = path[len('/cygdrive/'):]
321 path = path[:1] + ':' + path[1:]
322 return path
323
324def win32_to_unix_path(path):
325 if path is not None:
326 path = path.replace('\\', '/')
327 return path
328
329_RE_SHEBANG = re.compile(r'^\#!\s?([^\s]+)(?:\s([^\s]+))?')
330_SHEBANG_CMDS = {
331 '/usr/bin/env': 'env',
332 '/bin/sh': 'pysh',
333 'python': 'python',
334}
335
336def resolve_shebang(path, ignoreshell=False):
337 """Return a list of arguments as shebang interpreter call or an empty list
338 if path does not refer to an executable script.
339 See <http://www.opengroup.org/austin/docs/austin_51r2.txt>.
340
341 ignoreshell - set to True to ignore sh shebangs. Return an empty list instead.
342 """
343 try:
344 f = file(path)
345 try:
346 # At most 80 characters in the first line
347 header = f.read(80).splitlines()[0]
348 finally:
349 f.close()
350
351 m = _RE_SHEBANG.search(header)
352 if not m:
353 return []
354 cmd, arg = m.group(1,2)
355 if os.path.isfile(cmd):
356 # Keep this one, the hg script for instance contains a weird windows
357 # shebang referencing the current python install.
358 cmdfile = os.path.basename(cmd).lower()
359 if cmdfile == 'python.exe':
360 cmd = 'python'
361 pass
362 elif cmd not in _SHEBANG_CMDS:
363 raise CommandNotFound('Unknown interpreter "%s" referenced in '\
364 'shebang' % header)
365 cmd = _SHEBANG_CMDS.get(cmd)
366 if cmd is None or (ignoreshell and cmd == 'pysh'):
367 return []
368 if arg is None:
369 return [cmd, win32_to_unix_path(path)]
370 return [cmd, arg, win32_to_unix_path(path)]
371 except IOError as e:
372 if e.errno!=errno.ENOENT and \
373 (e.errno!=errno.EPERM and not os.path.isdir(path)): # Opening a directory raises EPERM
374 raise
375 return []
376
377def win32_find_in_path(name, path):
378 if isinstance(path, str):
379 path = path.split(os.pathsep)
380
381 exts = os.environ.get('PATHEXT', '').lower().split(os.pathsep)
382 for p in path:
383 p_name = os.path.join(p, name)
384
385 prefix = resolve_shebang(p_name)
386 if prefix:
387 return prefix
388
389 for ext in exts:
390 p_name_ext = p_name + ext
391 if os.path.exists(p_name_ext):
392 return [win32_to_unix_path(p_name_ext)]
393 return []
394
395class Traps(dict):
396 def __setitem__(self, key, value):
397 if key not in ('EXIT',):
398 raise NotImplementedError()
399 super(Traps, self).__setitem__(key, value)
400
401# IFS white spaces character class
402_IFS_WHITESPACES = (' ', '\t', '\n')
403
404class Environment:
405 """Environment holds environment variables, export table, function
406 definitions and whatever is defined in 2.12 "Shell Execution Environment",
407 redirection excepted.
408 """
409 def __init__(self, pwd):
410 self._opt = set() #Shell options
411
412 self._functions = {}
413 self._env = {'?': '0', '#': '0'}
414 self._exported = set([
415 'HOME', 'IFS', 'PATH'
416 ])
417
418 # Set environment vars with side-effects
419 self._ifs_ws = None # Set of IFS whitespace characters
420 self._ifs_re = None # Regular expression used to split between words using IFS classes
421 self['IFS'] = ''.join(_IFS_WHITESPACES) #Default environment values
422 self['PWD'] = pwd
423 self.traps = Traps()
424
425 def clone(self, subshell=False):
426 env = Environment(self['PWD'])
427 env._opt = set(self._opt)
428 for k,v in self.get_variables().iteritems():
429 if k in self._exported:
430 env.export(k,v)
431 elif subshell:
432 env[k] = v
433
434 if subshell:
435 env._functions = dict(self._functions)
436
437 return env
438
439 def __getitem__(self, key):
440 if key in ('@', '*', '-', '$'):
441 raise NotImplementedError('%s is not implemented' % repr(key))
442 return self._env[key]
443
444 def get(self, key, defval=None):
445 try:
446 return self[key]
447 except KeyError:
448 return defval
449
450 def __setitem__(self, key, value):
451 if key=='IFS':
452 # Update the whitespace/non-whitespace classes
453 self._update_ifs(value)
454 elif key=='PWD':
455 pwd = os.path.abspath(value)
456 if not os.path.isdir(pwd):
457 raise VarAssignmentError('Invalid directory %s' % value)
458 value = pwd
459 elif key in ('?', '!'):
460 value = str(int(value))
461 self._env[key] = value
462
463 def __delitem__(self, key):
464 if key in ('IFS', 'PWD', '?'):
465 raise VarAssignmentError('%s cannot be unset' % key)
466 del self._env[key]
467
468 def __contains__(self, item):
469 return item in self._env
470
471 def set_positional_args(self, args):
472 """Set the content of 'args' as positional argument from 1 to len(args).
473 Return previous argument as a list of strings.
474 """
475 # Save and remove previous arguments
476 prevargs = []
477 for i in xrange(int(self._env['#'])):
478 i = str(i+1)
479 prevargs.append(self._env[i])
480 del self._env[i]
481 self._env['#'] = '0'
482
483 #Set new ones
484 for i,arg in enumerate(args):
485 self._env[str(i+1)] = str(arg)
486 self._env['#'] = str(len(args))
487
488 return prevargs
489
490 def get_positional_args(self):
491 return [self._env[str(i+1)] for i in xrange(int(self._env['#']))]
492
493 def get_variables(self):
494 return dict(self._env)
495
496 def export(self, key, value=None):
497 if value is not None:
498 self[key] = value
499 self._exported.add(key)
500
501 def get_exported(self):
502 return [(k,self._env.get(k)) for k in self._exported]
503
504 def split_fields(self, word):
505 if not self._ifs_ws or not word:
506 return [word]
507 return re.split(self._ifs_re, word)
508
509 def _update_ifs(self, value):
510 """Update the split_fields related variables when IFS character set is
511 changed.
512 """
513 # TODO: handle NULL IFS
514
515 # Separate characters in whitespace and non-whitespace
516 chars = set(value)
517 ws = [c for c in chars if c in _IFS_WHITESPACES]
518 nws = [c for c in chars if c not in _IFS_WHITESPACES]
519
520 # Keep whitespaces in a string for left and right stripping
521 self._ifs_ws = ''.join(ws)
522
523 # Build a regexp to split fields
524 trailing = '[' + ''.join([re.escape(c) for c in ws]) + ']'
525 if nws:
526 # First, the single non-whitespace occurence.
527 nws = '[' + ''.join([re.escape(c) for c in nws]) + ']'
528 nws = '(?:' + trailing + '*' + nws + trailing + '*' + '|' + trailing + '+)'
529 else:
530 # Then mix all parts with quantifiers
531 nws = trailing + '+'
532 self._ifs_re = re.compile(nws)
533
534 def has_opt(self, opt, val=None):
535 return (opt, val) in self._opt
536
537 def set_opt(self, opt, val=None):
538 self._opt.add((opt, val))
539
540 def find_in_path(self, name, pwd=False):
541 path = self._env.get('PATH', '').split(os.pathsep)
542 if pwd:
543 path[:0] = [self['PWD']]
544 if os.name == 'nt':
545 return win32_find_in_path(name, self._env.get('PATH', ''))
546 else:
547 raise NotImplementedError()
548
549 def define_function(self, name, body):
550 if not is_name(name):
551 raise ShellSyntaxError('%s is not a valid function name' % repr(name))
552 self._functions[name] = body
553
554 def remove_function(self, name):
555 del self._functions[name]
556
557 def is_function(self, name):
558 return name in self._functions
559
560 def get_function(self, name):
561 return self._functions.get(name)
562
563
564name_charset = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_'
565name_charset = dict(zip(name_charset,name_charset))
566
567def match_name(s):
568 """Return the length in characters of the longest prefix made of name
569 allowed characters in s.
570 """
571 for i,c in enumerate(s):
572 if c not in name_charset:
573 return s[:i]
574 return s
575
576def is_name(s):
577 return len([c for c in s if c not in name_charset])<=0
578
579def is_special_param(c):
580 return len(c)==1 and c in ('@','*','#','?','-','$','!','0')
581
582def utility_not_implemented(name, *args, **kwargs):
583 raise NotImplementedError('%s utility is not implemented' % name)
584
585
586class Utility:
587 """Define utilities properties:
588 func -- utility callable. See builtin module for utility samples.
589 is_special -- see XCU 2.8.
590 """
591 def __init__(self, func, is_special=0):
592 self.func = func
593 self.is_special = bool(is_special)
594
595
596def encodeargs(args):
597 def encodearg(s):
598 lines = base64.encodestring(s)
599 lines = [l.splitlines()[0] for l in lines]
600 return ''.join(lines)
601
602 s = pickle.dumps(args)
603 return encodearg(s)
604
605def decodeargs(s):
606 s = base64.decodestring(s)
607 return pickle.loads(s)
608
609
610class GlobError(Exception):
611 pass
612
613class Options:
614 def __init__(self):
615 # True if Mercurial operates with binary streams
616 self.hgbinary = True
617
618class Interpreter:
619 # Implementation is very basic: the execute() method just makes a DFS on the
620 # AST and execute nodes one by one. Nodes are tuple (name,obj) where name
621 # is a string identifier and obj the AST element returned by the parser.
622 #
623 # Handler are named after the node identifiers.
624 # TODO: check node names and remove the switch in execute with some
625 # dynamic getattr() call to find node handlers.
626 """Shell interpreter.
627
628 The following debugging flags can be passed:
629 debug-parsing - enable PLY debugging.
630 debug-tree - print the generated AST.
631 debug-cmd - trace command execution before word expansion, plus exit status.
632 debug-utility - trace utility execution.
633 """
634
635 # List supported commands.
636 COMMANDS = {
637 'cat': Utility(builtin.utility_cat,),
638 'cd': Utility(builtin.utility_cd,),
639 ':': Utility(builtin.utility_colon,),
640 'echo': Utility(builtin.utility_echo),
641 'env': Utility(builtin.utility_env),
642 'exit': Utility(builtin.utility_exit),
643 'export': Utility(builtin.builtin_export, is_special=1),
644 'egrep': Utility(builtin.utility_egrep),
645 'fgrep': Utility(builtin.utility_fgrep),
646 'gunzip': Utility(builtin.utility_gunzip),
647 'kill': Utility(builtin.utility_kill),
648 'mkdir': Utility(builtin.utility_mkdir),
649 'netstat': Utility(builtin.utility_netstat),
650 'printf': Utility(builtin.utility_printf),
651 'pwd': Utility(builtin.utility_pwd),
652 'return': Utility(builtin.builtin_return, is_special=1),
653 'sed': Utility(builtin.utility_sed,),
654 'set': Utility(builtin.builtin_set,),
655 'shift': Utility(builtin.builtin_shift,),
656 'sleep': Utility(builtin.utility_sleep,),
657 'sort': Utility(builtin.utility_sort,),
658 'trap': Utility(builtin.builtin_trap, is_special=1),
659 'true': Utility(builtin.utility_true),
660 'unset': Utility(builtin.builtin_unset, is_special=1),
661 'wait': Utility(builtin.builtin_wait, is_special=1),
662 }
663
664 def __init__(self, pwd, debugflags = [], env=None, redirs=None, stdin=None,
665 stdout=None, stderr=None, opts=Options()):
666 self._env = env
667 if self._env is None:
668 self._env = Environment(pwd)
669 self._children = {}
670
671 self._redirs = redirs
672 self._close_redirs = False
673
674 if self._redirs is None:
675 if stdin is None:
676 stdin = sys.stdin
677 if stdout is None:
678 stdout = sys.stdout
679 if stderr is None:
680 stderr = sys.stderr
681 stdin = FileWrapper('r', stdin, False)
682 stdout = FileWrapper('w', stdout, False)
683 stderr = FileWrapper('w', stderr, False)
684 self._redirs = Redirections(stdin, stdout, stderr)
685 self._close_redirs = True
686
687 self._debugflags = list(debugflags)
688 self._logfile = sys.stderr
689 self._options = opts
690
691 def close(self):
692 """Must be called when the interpreter is no longer used."""
693 script = self._env.traps.get('EXIT')
694 if script:
695 try:
696 self.execute_script(script=script)
697 except:
698 pass
699
700 if self._redirs is not None and self._close_redirs:
701 self._redirs.close()
702 self._redirs = None
703
704 def log(self, s):
705 self._logfile.write(s)
706 self._logfile.flush()
707
708 def __getitem__(self, key):
709 return self._env[key]
710
711 def __setitem__(self, key, value):
712 self._env[key] = value
713
714 def options(self):
715 return self._options
716
717 def redirect(self, redirs, ios):
718 def add_redir(io):
719 if isinstance(io, pyshyacc.IORedirect):
720 redirs.add(self, io.op, io.filename, io.io_number)
721 else:
722 redirs.add_here_document(self, io.name, io.content, io.io_number)
723
724 map(add_redir, ios)
725 return redirs
726
727 def execute_script(self, script=None, ast=None, sourced=False,
728 scriptpath=None):
729 """If script is not None, parse the input. Otherwise takes the supplied
730 AST. Then execute the AST.
731 Return the script exit status.
732 """
733 try:
734 if scriptpath is not None:
735 self._env['0'] = os.path.abspath(scriptpath)
736
737 if script is not None:
738 debug_parsing = ('debug-parsing' in self._debugflags)
739 cmds, script = pyshyacc.parse(script, True, debug_parsing)
740 if 'debug-tree' in self._debugflags:
741 pyshyacc.print_commands(cmds, self._logfile)
742 self._logfile.flush()
743 else:
744 cmds, script = ast, ''
745
746 status = 0
747 for cmd in cmds:
748 try:
749 status = self.execute(cmd)
750 except ExitSignal as e:
751 if sourced:
752 raise
753 status = int(e.args[0])
754 return status
755 except ShellError:
756 self._env['?'] = 1
757 raise
758 if 'debug-utility' in self._debugflags or 'debug-cmd' in self._debugflags:
759 self.log('returncode ' + str(status)+ '\n')
760 return status
761 except CommandNotFound as e:
762 print >>self._redirs.stderr, str(e)
763 self._redirs.stderr.flush()
764 # Command not found by non-interactive shell
765 # return 127
766 raise
767 except RedirectionError as e:
768 # TODO: should be handled depending on the utility status
769 print >>self._redirs.stderr, str(e)
770 self._redirs.stderr.flush()
771 # Command not found by non-interactive shell
772 # return 127
773 raise
774
775 def dotcommand(self, env, args):
776 if len(args) < 1:
777 raise ShellError('. expects at least one argument')
778 path = args[0]
779 if '/' not in path:
780 found = env.find_in_path(args[0], True)
781 if found:
782 path = found[0]
783 script = file(path).read()
784 return self.execute_script(script=script, sourced=True)
785
786 def execute(self, token, redirs=None):
787 """Execute and AST subtree with supplied redirections overriding default
788 interpreter ones.
789 Return the exit status.
790 """
791 if not token:
792 return 0
793
794 if redirs is None:
795 redirs = self._redirs
796
797 if isinstance(token, list):
798 # Commands sequence
799 res = 0
800 for t in token:
801 res = self.execute(t, redirs)
802 return res
803
804 type, value = token
805 status = 0
806 if type=='simple_command':
807 redirs_copy = redirs.clone()
808 try:
809 # TODO: define and handle command return values
810 # TODO: implement set -e
811 status = self._execute_simple_command(value, redirs_copy)
812 finally:
813 redirs_copy.close()
814 elif type=='pipeline':
815 status = self._execute_pipeline(value, redirs)
816 elif type=='and_or':
817 status = self._execute_and_or(value, redirs)
818 elif type=='for_clause':
819 status = self._execute_for_clause(value, redirs)
820 elif type=='while_clause':
821 status = self._execute_while_clause(value, redirs)
822 elif type=='function_definition':
823 status = self._execute_function_definition(value, redirs)
824 elif type=='brace_group':
825 status = self._execute_brace_group(value, redirs)
826 elif type=='if_clause':
827 status = self._execute_if_clause(value, redirs)
828 elif type=='subshell':
829 status = self.subshell(ast=value.cmds, redirs=redirs)
830 elif type=='async':
831 status = self._asynclist(value)
832 elif type=='redirect_list':
833 redirs_copy = self.redirect(redirs.clone(), value.redirs)
834 try:
835 status = self.execute(value.cmd, redirs_copy)
836 finally:
837 redirs_copy.close()
838 else:
839 raise NotImplementedError('Unsupported token type ' + type)
840
841 if status < 0:
842 status = 255
843 return status
844
845 def _execute_if_clause(self, if_clause, redirs):
846 cond_status = self.execute(if_clause.cond, redirs)
847 if cond_status==0:
848 return self.execute(if_clause.if_cmds, redirs)
849 else:
850 return self.execute(if_clause.else_cmds, redirs)
851
852 def _execute_brace_group(self, group, redirs):
853 status = 0
854 for cmd in group.cmds:
855 status = self.execute(cmd, redirs)
856 return status
857
858 def _execute_function_definition(self, fundef, redirs):
859 self._env.define_function(fundef.name, fundef.body)
860 return 0
861
862 def _execute_while_clause(self, while_clause, redirs):
863 status = 0
864 while 1:
865 cond_status = 0
866 for cond in while_clause.condition:
867 cond_status = self.execute(cond, redirs)
868
869 if cond_status:
870 break
871
872 for cmd in while_clause.cmds:
873 status = self.execute(cmd, redirs)
874
875 return status
876
877 def _execute_for_clause(self, for_clause, redirs):
878 if not is_name(for_clause.name):
879 raise ShellSyntaxError('%s is not a valid name' % repr(for_clause.name))
880 items = mappend(self.expand_token, for_clause.items)
881
882 status = 0
883 for item in items:
884 self._env[for_clause.name] = item
885 for cmd in for_clause.cmds:
886 status = self.execute(cmd, redirs)
887 return status
888
889 def _execute_and_or(self, or_and, redirs):
890 res = self.execute(or_and.left, redirs)
891 if (or_and.op=='&&' and res==0) or (or_and.op!='&&' and res!=0):
892 res = self.execute(or_and.right, redirs)
893 return res
894
895 def _execute_pipeline(self, pipeline, redirs):
896 if len(pipeline.commands)==1:
897 status = self.execute(pipeline.commands[0], redirs)
898 else:
899 # Execute all commands one after the other
900 status = 0
901 inpath, outpath = None, None
902 try:
903 # Commands inputs and outputs cannot really be plugged as done
904 # by a real shell. Run commands sequentially and chain their
905 # input/output throught temporary files.
906 tmpfd, inpath = tempfile.mkstemp()
907 os.close(tmpfd)
908 tmpfd, outpath = tempfile.mkstemp()
909 os.close(tmpfd)
910
911 inpath = win32_to_unix_path(inpath)
912 outpath = win32_to_unix_path(outpath)
913
914 for i, cmd in enumerate(pipeline.commands):
915 call_redirs = redirs.clone()
916 try:
917 if i!=0:
918 call_redirs.add(self, '<', inpath)
919 if i!=len(pipeline.commands)-1:
920 call_redirs.add(self, '>', outpath)
921
922 status = self.execute(cmd, call_redirs)
923
924 # Chain inputs/outputs
925 inpath, outpath = outpath, inpath
926 finally:
927 call_redirs.close()
928 finally:
929 if inpath: os.remove(inpath)
930 if outpath: os.remove(outpath)
931
932 if pipeline.reverse_status:
933 status = int(not status)
934 self._env['?'] = status
935 return status
936
937 def _execute_function(self, name, args, interp, env, stdin, stdout, stderr, *others):
938 assert interp is self
939
940 func = env.get_function(name)
941 #Set positional parameters
942 prevargs = None
943 try:
944 prevargs = env.set_positional_args(args)
945 try:
946 redirs = Redirections(stdin.dup(), stdout.dup(), stderr.dup())
947 try:
948 status = self.execute(func, redirs)
949 finally:
950 redirs.close()
951 except ReturnSignal as e:
952 status = int(e.args[0])
953 env['?'] = status
954 return status
955 finally:
956 #Reset positional parameters
957 if prevargs is not None:
958 env.set_positional_args(prevargs)
959
960 def _execute_simple_command(self, token, redirs):
961 """Can raise ReturnSignal when return builtin is called, ExitSignal when
962 exit is called, and other shell exceptions upon builtin failures.
963 """
964 debug_command = 'debug-cmd' in self._debugflags
965 if debug_command:
966 self.log('word' + repr(token.words) + '\n')
967 self.log('assigns' + repr(token.assigns) + '\n')
968 self.log('redirs' + repr(token.redirs) + '\n')
969
970 is_special = None
971 env = self._env
972
973 try:
974 # Word expansion
975 args = []
976 for word in token.words:
977 args += self.expand_token(word)
978 if is_special is None and args:
979 is_special = env.is_function(args[0]) or \
980 (args[0] in self.COMMANDS and self.COMMANDS[args[0]].is_special)
981
982 if debug_command:
983 self.log('_execute_simple_command' + str(args) + '\n')
984
985 if not args:
986 # Redirections happen is a subshell
987 redirs = redirs.clone()
988 elif not is_special:
989 env = self._env.clone()
990
991 # Redirections
992 self.redirect(redirs, token.redirs)
993
994 # Variables assignments
995 res = 0
996 for type,(k,v) in token.assigns:
997 status, expanded = self.expand_variable((k,v))
998 if status is not None:
999 res = status
1000 if args:
1001 env.export(k, expanded)
1002 else:
1003 env[k] = expanded
1004
1005 if args and args[0] in ('.', 'source'):
1006 res = self.dotcommand(env, args[1:])
1007 elif args:
1008 if args[0] in self.COMMANDS:
1009 command = self.COMMANDS[args[0]]
1010 elif env.is_function(args[0]):
1011 command = Utility(self._execute_function, is_special=True)
1012 else:
1013 if not '/' in args[0].replace('\\', '/'):
1014 cmd = env.find_in_path(args[0])
1015 if not cmd:
1016 # TODO: test error code on unknown command => 127
1017 raise CommandNotFound('Unknown command: "%s"' % args[0])
1018 else:
1019 # Handle commands like '/cygdrive/c/foo.bat'
1020 cmd = cygwin_to_windows_path(args[0])
1021 if not os.path.exists(cmd):
1022 raise CommandNotFound('%s: No such file or directory' % args[0])
1023 shebang = resolve_shebang(cmd)
1024 if shebang:
1025 cmd = shebang
1026 else:
1027 cmd = [cmd]
1028 args[0:1] = cmd
1029 command = Utility(builtin.run_command)
1030
1031 # Command execution
1032 if 'debug-cmd' in self._debugflags:
1033 self.log('redirections ' + str(redirs) + '\n')
1034
1035 res = command.func(args[0], args[1:], self, env,
1036 redirs.stdin(), redirs.stdout(),
1037 redirs.stderr(), self._debugflags)
1038
1039 if self._env.has_opt('-x'):
1040 # Trace command execution in shell environment
1041 # BUG: would be hard to reproduce a real shell behaviour since
1042 # the AST is not annotated with source lines/tokens.
1043 self._redirs.stdout().write(' '.join(args))
1044
1045 except ReturnSignal:
1046 raise
1047 except ShellError as e:
1048 if is_special or isinstance(e, (ExitSignal,
1049 ShellSyntaxError, ExpansionError)):
1050 raise e
1051 self._redirs.stderr().write(str(e)+'\n')
1052 return 1
1053
1054 return res
1055
1056 def expand_token(self, word):
1057 """Expand a word as specified in [2.6 Word Expansions]. Return the list
1058 of expanded words.
1059 """
1060 status, wtrees = self._expand_word(word)
1061 return map(pyshlex.wordtree_as_string, wtrees)
1062
1063 def expand_variable(self, word):
1064 """Return a status code (or None if no command expansion occurred)
1065 and a single word.
1066 """
1067 status, wtrees = self._expand_word(word, pathname=False, split=False)
1068 words = map(pyshlex.wordtree_as_string, wtrees)
1069 assert len(words)==1
1070 return status, words[0]
1071
1072 def expand_here_document(self, word):
1073 """Return the expanded document as a single word. The here document is
1074 assumed to be unquoted.
1075 """
1076 status, wtrees = self._expand_word(word, pathname=False,
1077 split=False, here_document=True)
1078 words = map(pyshlex.wordtree_as_string, wtrees)
1079 assert len(words)==1
1080 return words[0]
1081
1082 def expand_redirection(self, word):
1083 """Return a single word."""
1084 return self.expand_variable(word)[1]
1085
1086 def get_env(self):
1087 return self._env
1088
1089 def _expand_word(self, token, pathname=True, split=True, here_document=False):
1090 wtree = pyshlex.make_wordtree(token[1], here_document=here_document)
1091
1092 # TODO: implement tilde expansion
1093 def expand(wtree):
1094 """Return a pseudo wordtree: the tree or its subelements can be empty
1095 lists when no value result from the expansion.
1096 """
1097 status = None
1098 for part in wtree:
1099 if not isinstance(part, list):
1100 continue
1101 if part[0]in ("'", '\\'):
1102 continue
1103 elif part[0] in ('`', '$('):
1104 status, result = self._expand_command(part)
1105 part[:] = result
1106 elif part[0] in ('$', '${'):
1107 part[:] = self._expand_parameter(part, wtree[0]=='"', split)
1108 elif part[0] in ('', '"'):
1109 status, result = expand(part)
1110 part[:] = result
1111 else:
1112 raise NotImplementedError('%s expansion is not implemented'
1113 % part[0])
1114 # [] is returned when an expansion result in no-field,
1115 # like an empty $@
1116 wtree = [p for p in wtree if p != []]
1117 if len(wtree) < 3:
1118 return status, []
1119 return status, wtree
1120
1121 status, wtree = expand(wtree)
1122 if len(wtree) == 0:
1123 return status, wtree
1124 wtree = pyshlex.normalize_wordtree(wtree)
1125
1126 if split:
1127 wtrees = self._split_fields(wtree)
1128 else:
1129 wtrees = [wtree]
1130
1131 if pathname:
1132 wtrees = mappend(self._expand_pathname, wtrees)
1133
1134 wtrees = map(self._remove_quotes, wtrees)
1135 return status, wtrees
1136
1137 def _expand_command(self, wtree):
1138 # BUG: there is something to do with backslashes and quoted
1139 # characters here
1140 command = pyshlex.wordtree_as_string(wtree[1:-1])
1141 status, output = self.subshell_output(command)
1142 return status, ['', output, '']
1143
1144 def _expand_parameter(self, wtree, quoted=False, split=False):
1145 """Return a valid wtree or an empty list when no parameter results."""
1146 # Get the parameter name
1147 # TODO: implement weird expansion rules with ':'
1148 name = pyshlex.wordtree_as_string(wtree[1:-1])
1149 if not is_name(name) and not is_special_param(name):
1150 raise ExpansionError('Bad substitution "%s"' % name)
1151 # TODO: implement special parameters
1152 if name in ('@', '*'):
1153 args = self._env.get_positional_args()
1154 if len(args) == 0:
1155 return []
1156 if len(args)<2:
1157 return ['', ''.join(args), '']
1158
1159 sep = self._env.get('IFS', '')[:1]
1160 if split and quoted and name=='@':
1161 # Introduce a new token to tell the caller that these parameters
1162 # cause a split as specified in 2.5.2
1163 return ['@'] + args + ['']
1164 else:
1165 return ['', sep.join(args), '']
1166
1167 return ['', self._env.get(name, ''), '']
1168
1169 def _split_fields(self, wtree):
1170 def is_empty(split):
1171 return split==['', '', '']
1172
1173 def split_positional(quoted):
1174 # Return a list of wtree split according positional parameters rules.
1175 # All remaining '@' groups are removed.
1176 assert quoted[0]=='"'
1177
1178 splits = [[]]
1179 for part in quoted:
1180 if not isinstance(part, list) or part[0]!='@':
1181 splits[-1].append(part)
1182 else:
1183 # Empty or single argument list were dealt with already
1184 assert len(part)>3
1185 # First argument must join with the beginning part of the original word
1186 splits[-1].append(part[1])
1187 # Create double-quotes expressions for every argument after the first
1188 for arg in part[2:-1]:
1189 splits[-1].append('"')
1190 splits.append(['"', arg])
1191 return splits
1192
1193 # At this point, all expansions but pathnames have occured. Only quoted
1194 # and positional sequences remain. Thus, all candidates for field splitting
1195 # are in the tree root, or are positional splits ('@') and lie in root
1196 # children.
1197 if not wtree or wtree[0] not in ('', '"'):
1198 # The whole token is quoted or empty, nothing to split
1199 return [wtree]
1200
1201 if wtree[0]=='"':
1202 wtree = ['', wtree, '']
1203
1204 result = [['', '']]
1205 for part in wtree[1:-1]:
1206 if isinstance(part, list):
1207 if part[0]=='"':
1208 splits = split_positional(part)
1209 if len(splits)<=1:
1210 result[-1] += [part, '']
1211 else:
1212 # Terminate the current split
1213 result[-1] += [splits[0], '']
1214 result += splits[1:-1]
1215 # Create a new split
1216 result += [['', splits[-1], '']]
1217 else:
1218 result[-1] += [part, '']
1219 else:
1220 splits = self._env.split_fields(part)
1221 if len(splits)<=1:
1222 # No split
1223 result[-1][-1] += part
1224 else:
1225 # Terminate the current resulting part and create a new one
1226 result[-1][-1] += splits[0]
1227 result[-1].append('')
1228 result += [['', r, ''] for r in splits[1:-1]]
1229 result += [['', splits[-1]]]
1230 result[-1].append('')
1231
1232 # Leading and trailing empty groups come from leading/trailing blanks
1233 if result and is_empty(result[-1]):
1234 result[-1:] = []
1235 if result and is_empty(result[0]):
1236 result[:1] = []
1237 return result
1238
1239 def _expand_pathname(self, wtree):
1240 """See [2.6.6 Pathname Expansion]."""
1241 if self._env.has_opt('-f'):
1242 return [wtree]
1243
1244 # All expansions have been performed, only quoted sequences should remain
1245 # in the tree. Generate the pattern by folding the tree, escaping special
1246 # characters when appear quoted
1247 special_chars = '*?[]'
1248
1249 def make_pattern(wtree):
1250 subpattern = []
1251 for part in wtree[1:-1]:
1252 if isinstance(part, list):
1253 part = make_pattern(part)
1254 elif wtree[0]!='':
1255 for c in part:
1256 # Meta-characters cannot be quoted
1257 if c in special_chars:
1258 raise GlobError()
1259 subpattern.append(part)
1260 return ''.join(subpattern)
1261
1262 def pwd_glob(pattern):
1263 cwd = os.getcwd()
1264 os.chdir(self._env['PWD'])
1265 try:
1266 return glob.glob(pattern)
1267 finally:
1268 os.chdir(cwd)
1269
1270 #TODO: check working directory issues here wrt relative patterns
1271 try:
1272 pattern = make_pattern(wtree)
1273 paths = pwd_glob(pattern)
1274 except GlobError:
1275 # BUG: Meta-characters were found in quoted sequences. The should
1276 # have been used literally but this is unsupported in current glob module.
1277 # Instead we consider the whole tree must be used literally and
1278 # therefore there is no point in globbing. This is wrong when meta
1279 # characters are mixed with quoted meta in the same pattern like:
1280 # < foo*"py*" >
1281 paths = []
1282
1283 if not paths:
1284 return [wtree]
1285 return [['', path, ''] for path in paths]
1286
1287 def _remove_quotes(self, wtree):
1288 """See [2.6.7 Quote Removal]."""
1289
1290 def unquote(wtree):
1291 unquoted = []
1292 for part in wtree[1:-1]:
1293 if isinstance(part, list):
1294 part = unquote(part)
1295 unquoted.append(part)
1296 return ''.join(unquoted)
1297
1298 return ['', unquote(wtree), '']
1299
1300 def subshell(self, script=None, ast=None, redirs=None):
1301 """Execute the script or AST in a subshell, with inherited redirections
1302 if redirs is not None.
1303 """
1304 if redirs:
1305 sub_redirs = redirs
1306 else:
1307 sub_redirs = redirs.clone()
1308
1309 subshell = None
1310 try:
1311 subshell = Interpreter(None, self._debugflags, self._env.clone(True),
1312 sub_redirs, opts=self._options)
1313 return subshell.execute_script(script, ast)
1314 finally:
1315 if not redirs: sub_redirs.close()
1316 if subshell: subshell.close()
1317
1318 def subshell_output(self, script):
1319 """Execute the script in a subshell and return the captured output."""
1320 # Create temporary file to capture subshell output
1321 tmpfd, tmppath = tempfile.mkstemp()
1322 try:
1323 tmpfile = os.fdopen(tmpfd, 'wb')
1324 stdout = FileWrapper('w', tmpfile)
1325
1326 redirs = Redirections(self._redirs.stdin().dup(),
1327 stdout,
1328 self._redirs.stderr().dup())
1329 try:
1330 status = self.subshell(script=script, redirs=redirs)
1331 finally:
1332 redirs.close()
1333 redirs = None
1334
1335 # Extract subshell standard output
1336 tmpfile = open(tmppath, 'rb')
1337 try:
1338 output = tmpfile.read()
1339 return status, output.rstrip('\n')
1340 finally:
1341 tmpfile.close()
1342 finally:
1343 os.remove(tmppath)
1344
1345 def _asynclist(self, cmd):
1346 args = (self._env.get_variables(), cmd)
1347 arg = encodeargs(args)
1348 assert len(args) < 30*1024
1349 cmd = ['pysh.bat', '--ast', '-c', arg]
1350 p = subprocess.Popen(cmd, cwd=self._env['PWD'])
1351 self._children[p.pid] = p
1352 self._env['!'] = p.pid
1353 return 0
1354
1355 def wait(self, pids=None):
1356 if not pids:
1357 pids = self._children.keys()
1358
1359 status = 127
1360 for pid in pids:
1361 if pid not in self._children:
1362 continue
1363 p = self._children.pop(pid)
1364 status = p.wait()
1365
1366 return status
1367